[wildcards] support for CONFLICTING_TYPE_VARIABLE_AND_MEMBER_CLASS

Fixes: #56397

(This test is just representative. Coverage is supplied by the language and co19 tests.)

Newly passing tests:

 language/wildcard_variables/declarations/class_generic_type_parameter_test
language/wildcard_variables/declarations/class_member_test
language/wildcard_variables/initializing_formal_parameters/this_test


Change-Id: I656a70bf9315051de5c7bfb1ee34e46ba0b25032
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/379506
Commit-Queue: Phil Quitslund <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: pq

pkg/analyzer/lib/src/generated/error_verifier.dart

@@ -2534,6 +2534,8 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
   void _checkForConflictingClassTypeVariableErrorCodes() {
     var enclosingClass = _enclosingClass!;
     for (TypeParameterElement typeParameter in enclosingClass.typeParameters) {
+      if (typeParameter.isWildcardVariable) continue;
+
       String name = typeParameter.name;
       // name is same as the name of the enclosing class
       if (enclosingClass.name == name) {

pkg/analyzer/test/src/diagnostics/conflicting_type_variable_and_member_test.dart

@@ -75,6 +75,31 @@ class A<T> {
     ]);
   }
 
+  test_method_wildcard() async {
+    await assertErrorsInCode(r'''
+class A<_> {
+  _() {}
+}
+''', [
+      error(WarningCode.UNUSED_ELEMENT, 15, 1),
+    ]);
+  }
+
+  test_method_wildcard_preWildcards() async {
+    await assertErrorsInCode(r'''
+// @dart = 3.4
+// (pre wildcard-variables)
+
+class A<_> {
+  _() {}
+}
+''', [
+      error(CompileTimeErrorCode.CONFLICTING_TYPE_VARIABLE_AND_MEMBER_CLASS, 52,
+          1),
+      error(WarningCode.UNUSED_ELEMENT, 59, 1),
+    ]);
+  }
+
   test_setter() async {
     await assertErrorsInCode(r'''
 class A<T> {